Modern medicine has come a long way in its understanding of the brain and the disorders that affect it. While earlier generations thought that neuro-psychiatric disorders were best treated radically — with surgery, perhaps, or confinement in an asylum — we now know that mental illnesses, while they are centered in the brain, are quite often the result of biological, psychological, and social factors.

The National Institutes of Health estimates that more than 62 percent of Americans over the age of eighteen — one in four adults — has a diagnosable mental disorder. Serious disorders like depression, bipolar disorder, and drug dependence cost at least $193 billion annually in lost earnings alone and affect about 6 percent of U.S. adults — or one in every seventeen people.

Types of Disorders

Experts divide mental illnesses into a few categories, including:

Mood Disorders include major depression and bipolar disorder and involve persistent feelings of sadness. In bipolar disorder (sometimes termed manic-depressive disorder), the feelings of sadness alternate with a sense of euphoria or mania.

Anxiety Disorders are characterized by excessive nervousness or anticipation of disaster or danger, along with a general feeling of uncertainty. Anxiety disorders include phobias (such as a fear of heights or closed spaces), panic disorder, obsessive-compulsive disorder (OCD), and post-traumatic stress disorder (PTSD).

Developmental Disorders are problems that generally appear in childhood or infancy, and include autism and attention deficit hyperactivity disorder (ADHD).

Substance Abuse Disorders are centered on the abuse of alcohol and illicit drugs as well as prescription and over-the-counter (OTC) medications and substances like nicotine.